1. Field of the Invention
The present invention relates to camera systems, and more particularly to a camera system composed of a camera body and a camera accessory which is arranged to be electrically and mechanically connected to the camera body.
2. Description of Related Art
As one example of camera accessories arranged to be mounted on a camera body to operate under the control of the camera body and having an electrical connection portion, such as power supply and communication lines, and a mechanical connection portion for connection with the camera body, there is a motor drive device. The motor drive device is arranged to enhance the performance of the camera body itself by supplying electric power to the camera body and aiding the camera body in performing a film transporting action or a shutter charging action.
Further, on the motor drive device, a plurality of kinds of power sources, such as a primary battery and a secondary battery, can be selectively mounted. The camera body detects the kind of the battery mounted on the motor drive device and controls the motor drive device in such a drive mode that is suited for the capability of the power source mounted. In other words, in a case where a powerful battery is mounted on the motor drive device, the driving mode of the camera body and the motor drive device is shifted to a high-speed mode, so that a frame shooting speed indicative of the number of exposable frames per unit time can be increased.
In order to change the driving mode from one mode over to another by distinguishing and detecting the kind of the power source mounted on the motor drive device, connection parts for communication between the camera body and the motor drive device for detection of the kind of the power source and for control of the driving mode must be additionaly provided on both sides. However, spaces for such connection parts for communication between the camera body and the motor drive device are limited even for electrical circuit arrangement as well as mechanical arrangement. Therefore, the spaces for that purpose cannot be increased as necessary.
Further, in a case where the motor drive device has compatibility with a plurality of kinds of camera bodies, it is necessary to have some method for setting the combination of the motor drive device with each of the plurality of kinds of camera bodies. There are various conceivable methods for that purpose.
In a first method, the photographer inputs the combination of the motor drive device with the camera body by making some operation when mounting the motor drive device on the camera body.
In a second method, the combination of the motor drive device with the camera body is automatically recognized, and control over each other is carried out according to the combination recognized. This method necessitates an ID verifying process to be made, for example, by electric communication. It is, therefore, necessary to have communication connecting portions arranged at both the motor drive device and the camera body for ID verification.